This invention relates to ultra light weight load bearing cementious ceramic containing blocks, having high insulating properties, and a method of manufacturing such blocks inexpensively yet providing the block with the desired properties.
The need for building materials having higher thermal insulation properties has been recognized and a number of proposals to better insulate buildings have been made. The use of additional insulation may be necessary for certain applications, but in regard to the outer walls additional insulation would require a change in the conventional wall thickness. Such a change in the thickness of the wall, whether it be an exterior wall or an interior wall, would result in substantial increases in building construction costs.
Since concrete is a major component of most buildings the prior art abounds with proposals formulating a cement mix having the various properties of low thermal resistance, light weight and high strength. Frequently, this type of product is formulated by a mixture of a concrete mix including light weight expanded aggregate materials. However, such prior art concrete materials have not proved successful in attaining their objects and those materials having low thermal resistance (high "R" values) such as materials containing expanded perlite or vermiculite do not possess sufficient strength for structural use, while those materials having sufficient structural strength have low R values. In practice it is difficult to achieve the reductions in density theoretically possible with additions of particulate expanded ceramics because of the poor mechanical properties of the expanded ceramics. The process of mixing the expanded ceramics with cementious materials (cement or mixtures of cement) normally results in the fracture and attrition of the expanded ceramic into smaller high density fragments. Thus, no known prior art proposals have been able to attain the long sought after combination of properties of high strength, light weight and high R value. Examples of the known prior art materials include Dudley, et al U.S. Pat. No. 4,293,341; Dodson, et al U.S. Pat. No. 4,210,457; Gray U.S. Pat. No. 4,042,406; Bowles, et al U.S. Pat. No. 3,764,357 and Redsky U.S. Pat. No. 2,858,227. Gray illustrates the problem where a light weight block is proposed for non-load bearing interior partitions.